Pothead terminal



Oct. 23, 1934.

Filed Jan. l2. 1932 2 Sheets-Sheet. l4

ATTO R N EYS Oct. 23, 1934.

E. F. Wl SALISBURY ROTHEAD TERMINAL 2 Sheets-Shee Filed Jan. l2, 1932 lIl x.

ATTORNEYS Patented Oct. 1934 i UNITED STATES PATENT OFFICE 'to AnacondaWire &

Cable Company, New

York, N. Y., a corporation of Delaware Application January 12, 19:2,serial No. 586,168

4 Claims.

'I'his invention relates to improvements in terminals for electricconductors and in particular to what is known in the art as a potheadterminal.

The invention will be fully apparent from the v following detaileddescription when read in connection with the accompanying drawings andwill be pointed out with particularity in the appended claims.

In the 'drawingsz- Fig. 1 is a longitudinal vertical section through apothead embodying the invention;

Fig. 2 is a detail view illustrating the manner of assembling partsofthe pothead terminal of Fig. 1;

Fig. 3 is a horizontal section taken on line 3-3 of Fig. 1;

Fig. 4 is a vertical section similar -to Fig. 1, but illustrating amodification of the invention.

Referring in detail to the drawings, represents any fixed structure, towhich a pot or casing 12 is secured by means of bolts 14. The lowerextremity of the pot 12 is of substantially hollow frusta-conical form,as indicated at 16 andit has an axial aperture 18 at its extremity of adiameter siimciently large to permit the entrance of the enlarged partssecured to the end of the terminal to be hereinafter referred to.

At the top of the body, there is formed a flange 20 having acounter-sunk portion, in which is seated a gasket 22 formed of cork, orthe like.

A shoulder 24 formed on an insulator l26 is seated on the gasket 22.This insulator has a downwardly extending skirt portion 28, which makesa loose fit with the bore 30, at the upper part of tion 24 and alsoextending fora short distance upwardly there is a pad 32 formed offabric, or other suitable resilient material.

For detachably securing the insulator 26 to the body or casing, Iprovide a two part base ring, indicated as a whole at 34. This ring, asbest shown in Fig. 3, includes two substantially semicircular parts 36and 38, which aresecured to one another by transversely extending screws40. Each of these rings, is provided with a plurality of lugs 42 adaptedto receive the ends of bolts 44 which pass through the flange 20 of thepot or casing, thus drawing the shoulder 24 of the insulator rmlyagainst the gasket 22 seated on the flange of the pot or casing 12. l

The insulator 26 is provided with an axially extending, interior chamber46 having a diameter sufllciently large to permit the free passage ofthe enlarged pothead terminal to be presently referred to.

the pot or casing. Surrounding the shoulder por-V (cl. 17a-asa) Anelectric conductor 48usua1ly in the form of a stranded cable has securedto its terminal portion 50 a stem member, indicated as a whole at 52.This member has an interior socket 54 into which the extremity of theterminal portion 50 of the cable is securely fastened, the joint usuallybeing made permanent by soldering. The lower extremity of the stem 52 isin the form of an enlarged head 56 having screw threads on the exteriorthereof, which engage threads 58 formed 55 on the interior vof a tube orsleeve 60, formed of bakelite, ber, or similar dielectric material.

The cable 48 is wrapped with a plurality of layers of suitableinsulating material in any manner well known in the art. This insulatorwrapping being indicated at 62. Over the insulation, there is an outerlead sheath 64. The upper extremity of this sheath is flared outwardly,as indicated at 66, so as to form a seat for the tapered or beveled endof the sleeve 60. The sleeve 60 in its working position is screwed downover theenlargement -56 of the stem 52, so as to seat the beveledportion 68 firmly against the flared part 66 of the sheath. so as toform a hermetical seal. The sleeve 60 is provided with 80 a removabletapered closure plug 70, through which a suitable insulating compoundcan be inserted after the parts are assembled. This insulating compound,is indicated at 72, in Fig; 1.

, After filling up the void between the interior 35 of lthe sleeve 60and the exterior of the cable and its wrapping, the tapered plug '70 isnrmlyl screwed home, thus hermetically sealing the terminal portion 50of the cable.

The'stem 52 above referred tois provided with 90 a flange 74 ofnon-circular form. As illustrated, this flange is square in plan and itis seated against a similarly shaped gasket or washer 76, bothJ theflange and the gasket being accommodated in a square recess 78 eformedin the in- 95 terior'portion of the insulator. The shank 80 qi.' thestem 52 extendsv freely throughV an enlarged axial opening 82 oftheinsulator body and has Dardelet self-1ocking threads 84 formed thereon..These threads engage the interior threads formed on the hood mit 86.This nut has a petticoat portion 88, which depends from a bearingportion mi which is adapted to seat against the gasket 92 located on topof the insulator body. The hood nut has aI hexagonal portion 94adaptedfor engagement with a suit-f able wrench. When this hood nut isscrewed on the threads 84 of the shank of the terminal, it will beunderstood that the squared flange 'Z4 prevents the terminal fromturning relatively to 110,

this insulating material is introduced in the form of a liquid, orsemi-liquid, or semi-plastic mass, the same being forced in underpressure through an inlet port 104 formerly closed by a tapered pipeplug 106.

'I'o positively prevent leakage of the insulating compound from thelower part of the pot or casing, I provide a cone-like ring or thimble108, which is attached to the conical portion 16 of the pot. And overthe ring, I form a wiped joint 110, this joint of course readilyadhering to the llead sheath surrounding the cable.

In Fig. 4, I have illustrated a modification, in which many of the partsare the same as those above referred to and they are, therefore,indicated by like reference characters. The chief diiference betweenthis construction and that shown in Figs. 1 to 3 is that I omit thethreaded flange 56 of the terminal stem 52 and also the shell 60. -Inthis form of device, the lead sheath surrounding the cable terminates ata point below the insulator petticoat 28. This sheath is flaredoutwardly, as indicated at 112 and it has soldered thereto a stress cone114 adapted to distribute electrical stress well known in the art.

From the `foregoing, it will be appreciated that in my improvedconstruction Ithe insulator for the pothead terminal is secured to thepot or casing by the two part clamping ring Without the use 'of cementor the like. f

The described construction aims .to eliminate the usual line troubleswith potheads which are usually caused by the entrance of moisture atthe top of the struc-ture. The herein described structure, precludes theentrance of such -rnoisture, itbeing understood that the clamping actionof the hood nut 86 and the flange 74 will hermetically seal the interiorof vthe insulator, the gaskets 92 and 78 contributing materially to thisdesirable end. The self-locking threaded connection between the shank ofthe terminal stem and the hood nut makes it impossible to loosen thelaitter by vibration. The sleeve with its tapered lower extremity makesa substantially moisture .tight joint with the flared part ofthe leadsheath when filled with compound, thusl making a perfectly rtight joint,so that in the event that moisture should ,seep into the pot `or casingdue to leakage, or depletion'of the insulating filling, such moisturecannot reach the insulated wrapping around the conductor and thereby.;cause its breakdown. I

The 'above and other inherent advantages of the described potheadterminal will be readily apparent to those skilled inthe art.

While I have described quite precisely the design and construction ofcertain embodiments of. the invention herein illustrated, it is to beunderstood that the description and drawings are to be interpreted in anillustrative rather than 'a limiting sense since various modificationsmay be made by those skilled in the art without departure-from theinvention as defined in the appended claims.

What I claim isz- 1. In a device of the character described, apot-casing having a supporting flange, an insulator, means for securingthe insulator to said flange, said insulator having a dependingpetticoat portion extending downwardly from said flange into theinterior of the casing, a sheathed conductor extending through saidinsulator and having a flared portion spaced from fthe extremity of saidpetticoat portion, a terminal stem secured rto one end of saidconductor, a sleeve of insulating material'threaded on said stem andhaving a tapered portion for engagement with the iiared part of saidsheath, and means for clamping said terminal stem to said insulator.

2. In a device of the class described, a pot-casing, an insulatorsecured thereto, a sheathed conductor, a joint secured to the casing andsaid sheathed conductor, a terminal stem secured to anend of saidconductor within said insulator, said terminal stem having a sleeve ofinsulating material threaded on one end thereof, said sleeve having aportion shaped to wedgingly engage a portion of the sheath for theconductor, an abutment on said terminal stem, a gasket interposedbetween said abutment and part of the insulator body and a nut threadedon the extremity of sai-d shank and having a. hood portion extendingacross the top thereof.

3. In a device of theclass described, a fptcasing, an insulator securedthereto, a metalsheathed conductor having one end enclosed by saidinsulator, a joint uni-ting the casing to the sheafth of said conductor,a terminal stem secured to .the end of the conductor within saidinsulator, said terminal stem having a sleeve `of insulating materialthreaded thereon, the sleeve having a portion shaped-to wedgingly engagea portion of the conductor sheath, an abutment on said terminal stem, aVgasket interposed between said abutment and part of the insulator body,a nut threaded 'on the extremity of said shank and having a hood portionenclosing 'the top thereof, a conductor having a fitting secured theretoand means for clamping said fitting to said nut.

4. A pothead terminal of the character described including an insulator,an insulated conductor having va metallic protective sheath, a terminalstem clamped to said insulator and secured to said conductor, a sleeveof insulating material in screw .threaded engagement with said stem. andhaving one extremity in wedged engagement with said sheath, a pot orcasing for .supporting said insulator and separable meansv embracing theinsulator for securing it to said pot casing. Y i

' EDWARD F. W. SALISBURY.

